#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "llhttp.h"

#define CALLBACK_MAYBE(PARSER, NAME)                                           \
  do {                                                                         \
    const llhttp_settings_t *settings;                                         \
    settings = (const llhttp_settings_t *)(PARSER)->settings;                  \
    if (settings == NULL || settings->NAME == NULL) {                          \
      err = 0;                                                                 \
      break;                                                                   \
    }                                                                          \
    err = settings->NAME((PARSER));                                            \
  } while (0)

#define SPAN_CALLBACK_MAYBE(PARSER, NAME, START, LEN)                          \
  do {                                                                         \
    const llhttp_settings_t *settings;                                         \
    settings = (const llhttp_settings_t *)(PARSER)->settings;                  \
    if (settings == NULL || settings->NAME == NULL) {                          \
      err = 0;                                                                 \
      break;                                                                   \
    }                                                                          \
    err = settings->NAME((PARSER), (START), (LEN));                            \
    if (err == -1) {                                                           \
      err = HPE_USER;                                                          \
      llhttp_set_error_reason((PARSER), "Span callback error in " #NAME);      \
    }                                                                          \
  } while (0)

void llhttp_init(llhttp_t *parser, llhttp_type_t type,
                 const llhttp_settings_t *settings) {
  llhttp__internal_init(parser);

  parser->type = type;
  parser->settings = (void *)settings;
}

#if defined(__wasm__)

extern int wasm_on_message_begin(llhttp_t *p);
extern int wasm_on_url(llhttp_t *p, const char *at, size_t length);
extern int wasm_on_status(llhttp_t *p, const char *at, size_t length);
extern int wasm_on_header_field(llhttp_t *p, const char *at, size_t length);
extern int wasm_on_header_value(llhttp_t *p, const char *at, size_t length);
extern int wasm_on_headers_complete(llhttp_t *p, int status_code,
                                    uint8_t upgrade, int should_keep_alive);
extern int wasm_on_body(llhttp_t *p, const char *at, size_t length);
extern int wasm_on_message_complete(llhttp_t *p);

static int wasm_on_headers_complete_wrap(llhttp_t *p) {
  return wasm_on_headers_complete(p, p->status_code, p->upgrade,
                                  llhttp_should_keep_alive(p));
}

const llhttp_settings_t wasm_settings = {
    wasm_on_message_begin,
    wasm_on_url,
    wasm_on_status,
    NULL,
    NULL,
    wasm_on_header_field,
    wasm_on_header_value,
    NULL,
    NULL,
    wasm_on_headers_complete_wrap,
    wasm_on_body,
    wasm_on_message_complete,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
    NULL,
};

llhttp_t *llhttp_alloc(llhttp_type_t type) {
  llhttp_t *parser = malloc(sizeof(llhttp_t));
  llhttp_init(parser, type, &wasm_settings);
  return parser;
}

void llhttp_free(llhttp_t *parser) { free(parser); }

#endif // defined(__wasm__)

/* Some getters required to get stuff from the parser */

uint8_t llhttp_get_type(llhttp_t *parser) { return parser->type; }

uint8_t llhttp_get_http_major(llhttp_t *parser) { return parser->http_major; }

uint8_t llhttp_get_http_minor(llhttp_t *parser) { return parser->http_minor; }

uint8_t llhttp_get_method(llhttp_t *parser) { return parser->method; }

int llhttp_get_status_code(llhttp_t *parser) { return parser->status_code; }

uint8_t llhttp_get_upgrade(llhttp_t *parser) { return parser->upgrade; }

void llhttp_reset(llhttp_t *parser) {
  llhttp_type_t type = parser->type;
  const llhttp_settings_t *settings = parser->settings;
  void *data = parser->data;
  uint16_t lenient_flags = parser->lenient_flags;

  llhttp__internal_init(parser);

  parser->type = type;
  parser->settings = (void *)settings;
  parser->data = data;
  parser->lenient_flags = lenient_flags;
}

llhttp_errno_t llhttp_execute(llhttp_t *parser, const char *data, size_t len) {
  return llhttp__internal_execute(parser, data, data + len);
}

void llhttp_settings_init(llhttp_settings_t *settings) {
  memset(settings, 0, sizeof(*settings));
}

llhttp_errno_t llhttp_finish(llhttp_t *parser) {
  int err;

  /* We're in an error state. Don't bother doing anything. */
  if (parser->error != 0) {
    return 0;
  }

  switch (parser->finish) {
  case HTTP_FINISH_SAFE_WITH_CB:
    CALLBACK_MAYBE(parser, on_message_complete);
    if (err != HPE_OK)
      return err;

  /* FALLTHROUGH */
  case HTTP_FINISH_SAFE:
    return HPE_OK;
  case HTTP_FINISH_UNSAFE:
    parser->reason = "Invalid EOF state";
    return HPE_INVALID_EOF_STATE;
  default:
    abort();
  }
}

void llhttp_pause(llhttp_t *parser) {
  if (parser->error != HPE_OK) {
    return;
  }

  parser->error = HPE_PAUSED;
  parser->reason = "Paused";
}

void llhttp_resume(llhttp_t *parser) {
  if (parser->error != HPE_PAUSED) {
    return;
  }

  parser->error = 0;
}

void llhttp_resume_after_upgrade(llhttp_t *parser) {
  if (parser->error != HPE_PAUSED_UPGRADE) {
    return;
  }

  parser->error = 0;
}

llhttp_errno_t llhttp_get_errno(const llhttp_t *parser) {
  return parser->error;
}

const char *llhttp_get_error_reason(const llhttp_t *parser) {
  return parser->reason;
}

void llhttp_set_error_reason(llhttp_t *parser, const char *reason) {
  parser->reason = reason;
}

const char *llhttp_get_error_pos(const llhttp_t *parser) {
  return parser->error_pos;
}

const char *llhttp_errno_name(llhttp_errno_t err) {
#define HTTP_ERRNO_GEN(CODE, NAME, _)                                          \
  case HPE_##NAME:                                                             \
    return "HPE_" #NAME;
  switch (err) {
    HTTP_ERRNO_MAP(HTTP_ERRNO_GEN)
  default:
    abort();
  }
#undef HTTP_ERRNO_GEN
}

const char *llhttp_method_name(llhttp_method_t method) {
#define HTTP_METHOD_GEN(NUM, NAME, STRING)                                     \
  case HTTP_##NAME:                                                            \
    return #STRING;
  switch (method) {
    HTTP_ALL_METHOD_MAP(HTTP_METHOD_GEN)
  default:
    abort();
  }
#undef HTTP_METHOD_GEN
}

const char *llhttp_status_name(llhttp_status_t status) {
#define HTTP_STATUS_GEN(NUM, NAME, STRING)                                     \
  case HTTP_STATUS_##NAME:                                                     \
    return #STRING;
  switch (status) {
    HTTP_STATUS_MAP(HTTP_STATUS_GEN)
  default:
    abort();
  }
#undef HTTP_STATUS_GEN
}

void llhttp_set_lenient_headers(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_HEADERS;
  } else {
    parser->lenient_flags &= ~LENIENT_HEADERS;
  }
}

void llhttp_set_lenient_chunked_length(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_CHUNKED_LENGTH;
  } else {
    parser->lenient_flags &= ~LENIENT_CHUNKED_LENGTH;
  }
}

void llhttp_set_lenient_keep_alive(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_KEEP_ALIVE;
  } else {
    parser->lenient_flags &= ~LENIENT_KEEP_ALIVE;
  }
}

void llhttp_set_lenient_transfer_encoding(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_TRANSFER_ENCODING;
  } else {
    parser->lenient_flags &= ~LENIENT_TRANSFER_ENCODING;
  }
}

void llhttp_set_lenient_version(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_VERSION;
  } else {
    parser->lenient_flags &= ~LENIENT_VERSION;
  }
}

void llhttp_set_lenient_data_after_close(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_DATA_AFTER_CLOSE;
  } else {
    parser->lenient_flags &= ~LENIENT_DATA_AFTER_CLOSE;
  }
}

void llhttp_set_lenient_optional_lf_after_cr(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_OPTIONAL_LF_AFTER_CR;
  } else {
    parser->lenient_flags &= ~LENIENT_OPTIONAL_LF_AFTER_CR;
  }
}

void llhttp_set_lenient_optional_crlf_after_chunk(llhttp_t *parser,
                                                  int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_OPTIONAL_CRLF_AFTER_CHUNK;
  } else {
    parser->lenient_flags &= ~LENIENT_OPTIONAL_CRLF_AFTER_CHUNK;
  }
}

void llhttp_set_lenient_optional_cr_before_lf(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_OPTIONAL_CR_BEFORE_LF;
  } else {
    parser->lenient_flags &= ~LENIENT_OPTIONAL_CR_BEFORE_LF;
  }
}

void llhttp_set_lenient_spaces_after_chunk_size(llhttp_t *parser, int enabled) {
  if (enabled) {
    parser->lenient_flags |= LENIENT_SPACES_AFTER_CHUNK_SIZE;
  } else {
    parser->lenient_flags &= ~LENIENT_SPACES_AFTER_CHUNK_SIZE;
  }
}

/* Callbacks */

int llhttp__on_message_begin(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_message_begin);
  return err;
}

int llhttp__on_url(llhttp_t *s, const char *p, const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_url, p, endp - p);
  return err;
}

int llhttp__on_url_complete(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_url_complete);
  return err;
}

int llhttp__on_status(llhttp_t *s, const char *p, const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_status, p, endp - p);
  return err;
}

int llhttp__on_status_complete(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_status_complete);
  return err;
}

int llhttp__on_method(llhttp_t *s, const char *p, const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_method, p, endp - p);
  return err;
}

int llhttp__on_method_complete(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_method_complete);
  return err;
}

int llhttp__on_version(llhttp_t *s, const char *p, const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_version, p, endp - p);
  return err;
}

int llhttp__on_version_complete(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_version_complete);
  return err;
}

int llhttp__on_header_field(llhttp_t *s, const char *p, const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_header_field, p, endp - p);
  return err;
}

int llhttp__on_header_field_complete(llhttp_t *s, const char *p,
                                     const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_header_field_complete);
  return err;
}

int llhttp__on_header_value(llhttp_t *s, const char *p, const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_header_value, p, endp - p);
  return err;
}

int llhttp__on_header_value_complete(llhttp_t *s, const char *p,
                                     const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_header_value_complete);
  return err;
}

int llhttp__on_headers_complete(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_headers_complete);
  return err;
}

int llhttp__on_message_complete(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_message_complete);
  return err;
}

int llhttp__on_body(llhttp_t *s, const char *p, const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_body, p, endp - p);
  return err;
}

int llhttp__on_chunk_header(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_chunk_header);
  return err;
}

int llhttp__on_chunk_extension_name(llhttp_t *s, const char *p,
                                    const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_chunk_extension_name, p, endp - p);
  return err;
}

int llhttp__on_chunk_extension_name_complete(llhttp_t *s, const char *p,
                                             const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_chunk_extension_name_complete);
  return err;
}

int llhttp__on_chunk_extension_value(llhttp_t *s, const char *p,
                                     const char *endp) {
  int err;
  SPAN_CALLBACK_MAYBE(s, on_chunk_extension_value, p, endp - p);
  return err;
}

int llhttp__on_chunk_extension_value_complete(llhttp_t *s, const char *p,
                                              const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_chunk_extension_value_complete);
  return err;
}

int llhttp__on_chunk_complete(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_chunk_complete);
  return err;
}

int llhttp__on_reset(llhttp_t *s, const char *p, const char *endp) {
  int err;
  CALLBACK_MAYBE(s, on_reset);
  return err;
}

/* Private */

void llhttp__debug(llhttp_t *s, const char *p, const char *endp,
                   const char *msg) {
  if (p == endp) {
    fprintf(stderr, "p=%p type=%d flags=%02x next=null debug=%s\n", s, s->type,
            s->flags, msg);
  } else {
    fprintf(stderr, "p=%p type=%d flags=%02x next=%02x   debug=%s\n", s,
            s->type, s->flags, *p, msg);
  }
}
